While there is a large body of evidence that poor subjective sleep quality is related to lower subjective well-being, studies on the relation of objective sleep measures and subjective well-being are fewer in number and less consistent in their findings. Using data of the Survey of Mid-Life in the United States (MIDUS), we investigated whether duration and quality of sleep, assessed by actigraphy, were related to subjective well-being and whether this relationship was mediated by subjective sleep quality. Three hundred and thirteen mainly white American individuals from the general population and 128 urban-dwelling African American individuals between 35 and 85 years of age were studied cross-sectionally. Sleep duration, variability of sleep duration, sleep onset latency, and time awake after sleep onset were assessed by actigraphy over a period of 7 days. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index, positive psychological well-being and symptoms of psychological distress were assessed with the Satisfaction with Life Scale and the Mood and Anxiety Symptom Questionnaire. In both white and African Americans high day-to-day variability in sleep duration was related to lower levels of subjective well-being controlling age, gender, educational and marital status, and BMI. By contrast, sleep duration, sleep onset latency, and time awake after sleep onset were not related to subjective well-being controlling covariates and other sleep variables. Moreover, the relationship between variability in sleep duration and well-being was partially mediated by subjective sleep quality. The findings show that great day-to-day variability in sleep duration – more than average sleep duration – is related to poor subjective sleep quality and poor subjective well-being.

A variety of objective and subjective methods exist to assess insomnia. The Insomnia Severity Index (ISI) was developed to provide a brief self-report instrument useful to assess people’s perception of sleep complaints. The ISI was developed in English, and has been translated into several languages including German. Surprisingly, the psychometric properties of the German version have not been evaluated, although the ISI is often used with German-speaking populations. The psychometric properties of the ISI are tested in three independent samples: 1475 adolescents, 862 university students, and 533 police and emergency response service officers. In all three studies, participants provide information about insomnia (ISI), sleep quality (Pittsburgh Sleep Quality Index), and psychological functioning (diverse instruments). Descriptive statistics, gender differences, homogeneity and internal consistency, convergent validity, and factorial validity (including measurement invariance across genders) are examined in each sample. The findings show that the German version of the ISI has generally acceptable psychometric properties and sufficient concurrent validity. Confirmatory factor analyses show that a 1-factor solution achieves good model fit. Furthermore, measurement invariance across gender is supported in all three samples. While the ISI has been widely used in German-speaking countries, this study is the first to provide empirical evidence that the German version of this instrument has good psychometric properties and satisfactory convergent and factorial validity across various age groups and both men and women. Thus, the German version of the ISI can be recommended as a brief screening measure in German-speaking populations.

To examine the changes in mothers’ and fathers’ sleep satisfaction and sleep duration across pre-pregnancy, pregnancy, and the postpartum period of up to six years after birth; it also sought to determine potential protective and risk factors for sleep during that time. Participants in a large population-representative panel study from Germany reported sleep satisfaction and sleep duration in yearly interviews. During the observation period (2008–2015), 2,541 women and 2,118 men reported the birth of their first, second, or third child and provided longitudinal data for analysis. Fixed-effects regression models were used to analyze changes in sleep associated with childbirth. Sleep satisfaction and duration sharply declined with childbirth and reached a nadir during the first three months postpartum, with women more strongly affected (sleep satisfaction reduction compared with pre-pregnancy: women, 1.81 points on a 0 to 10 scale, d = 0.79 vs. men, 0.37 points, d = 0.16; sleep duration reduction compared with pre-pregnancy: women, 62 min, d = 0.90 vs. men, 13 min, d = 0.19). In both women and men, sleep satisfaction and duration did not fully recover for up to six years after the birth of their first child. Breastfeeding was associated with a slight decrease in maternal sleep satisfaction (0.72 points, d = 0.32) and duration (14 min, d = 0.21). Parental age, household income, and dual vs. single parenting were unrelated, or only very weakly related, to improved sleep. Following the sharp decline in sleep satisfaction and duration in the first months postpartum, neither mothers’ nor fathers’ sleep fully recovers to pre-pregnancy levels up to six years after the birth of their first child.